Semiconductor Pillars With Concave Surfaces for High Density Bonding

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Solution Overview

Problem

The existing flip chip bonding technology in semiconductor packages results in increased intervals or pitches between solder balls due to their spherical shape, limiting the integration density of semiconductor devices and packages.

Innovation Solution

The use of semiconductor devices and package substrates with pillars that have concave upper surfaces and substantially planar, vertical side surfaces, allowing for the placement of solder balls with a greater vertical height than horizontal width, thereby reducing the spacing between them and increasing integration density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spherical solder balls are used with sufficient volume for stable bonding, then bonding reliability is improved, but horizontal width and intervals between solder balls increase, reducing integration density

Engineering Contradiction:

Improvebonding reliabilityVSAvoidintegration density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent transitions from spherical solder balls to pillar-shaped structures with concave upper surfaces, changing the geometric dimensionality to optimize both bonding reliability and integration density. The vertical orientation allows solder balls to be positioned higher while maintaining smaller horizontal footprints.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent modifies the geometric parameters of the bonding structure by using pillars with concave upper surfaces instead of spheres, allowing the vertical height to be greater than the horizontal width, thereby achieving stable bonding with reduced pitch.

Inventive Principle:

Principle #35Parameter changes

2Strength

If larger solder balls are used to ensure stable bonding, then bonding strength is improved, but the pitch between adjacent solder balls increases, limiting manufacturing integration

Engineering Contradiction:

Improvebonding strengthVSAvoidpitch between solder balls

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The patent employs asymmetric pillar shapes with concave upper surfaces and substantially planar, substantially vertical side surfaces, allowing the structure to have greater height than width, thereby providing strong bonding with reduced horizontal pitch.

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If conventional spherical solder balls are used, then manufacturing process is simple, but intervals between pads and pillars must be larger, reducing device integration

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidarea occupied by bonding structures

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent changes the bonding structure from horizontal spherical arrangement to vertical pillar arrangement with concave surfaces, allowing solder balls to be positioned at elevated locations with smaller horizontal spacing, thereby reducing the area occupied while maintaining manufacturing feasibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9449930B2Semiconductor devices and package substrates having pillars and semiconductor packages and package stack structures having the same

Publication Date: 2016.09.20 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor device, a semiconductor package, and a package stack structure include a semiconductor substrate, a first bonding pad disposed on a first surface of the semiconductor substrate, and a first pillar disposed on the first bonding pad. An upper surface of the first pillar has a concave shape. Side surfaces of the first pillar are substantially planar.